Tollesbury Managed Sea Wall Retreat
Tollesbury Fleet English Nature incorporated in Natural England Map of Local Conservation Areas Site of the Managed Setback looking towards Old Hall Marshes & the sea Breach in the Old Sea wall English Nature (now incorporated in "Natural England") is managing this land as an experimental site for sea defence set-back. This involves building a new sea wall at a more landward location, breaching the old wall, and allowing saltmarsh to return to the intervening land. This new saltmarsh will act as a natural defence and help replace saltmarshes lost to erosion and historical reclamations in the Tollesbury Fleet. As the saltmarshes and the sea return farmland plants not tolerant of salt water, decline whilst fish other sea and marsh life returns The sea wall was breached in early August 1995. The trial will investigate all aspects of this sea defence technique, especially the best management methods for establishment of saltmarsh. This work is supported by the Flood and Coastal Defence research programme of the Ministry of Agriculture, Fisheries and Food. For more information, contact the Maritime Team, English Nature, Northminster House, Peterborough, PE1 1UA. |
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A full scale experimental site for managed setback of sea defences was set up in 1994 near Tollesbury in Essex. This is used to carry out a range of research projects. The aim is to improve understanding of the processes involved in managing setback of sea defences and the practical techniques required for its management in typical UK situations. The Tollesbury site is on the north side of the Blackwater Estuary in Essex. The main research project at Tollesbury is being carried out for MAFF ((Ministry of Agriculture, Fisheries & Food) jointly by English Nature and the Institute of Terrestrial Ecology (ITE). The Need For The Experiment Setback of sea defences is one of a range of options which flood defence authorities are encouraged to consider when existing defences reach the end of their useful lives. MAFF ((Ministry of Agriculture, Fisheries & Food) is investigating how setback can be managed for environmental gain and long term security of flood defences. A particular challenge is the development of management techniques which will enable the long term development of stable salt marsh on setback land. The Experimental Programme There are two major aspects to the experimental work: The 21 ha. (c. 50 acres, 1ha = 1 hect are = 2.471 acres) site was acquired by English Nature in 1994. The sea wall was breached in early August 1995. The monitoring of the botanical development of the site and plot scale experiments is being carried out by ITE (Institute of Terrestrial Ecology). Silsoe Research Institute are looking at the strength and stability of the soils within the site before and after inundation and ITE (Institute of Terrestrial Ecology) are carrying out pre- and post- breaching studies of invertebrates. Monitoring in the estuary is being carried out by IECS (Institute of Estuarine and Coastal Studies) under a separate research contract to the EA (Environment Agency). |
Proposals from other research funders to use the site to promote related research relevant to their own concerns will continue to be welcomed. |
The work connected with this major experiment is being reviewed by an advisory group with membership from EA (Environment Agency), English Nature, the Association of District Councils, the National Trust and the RSPB (Royal Society for the Protection of Birds), as well as the research contractors. |
CONTACTS:
English Nature Institute of Terrestrial Ecology HR Wallingford Ltd Institute of Estuarine and Coastal Studies Silsoe Research Institute |